The present invention relates to a process for the preparation of pulverulent heterogeneous substances.
It is known to prepare pulverulent heterogeneous substances from oxides and salts starting from a suspension, dispersion or emulsion.
Spray driers or similar apparatus are usually employed for the drying of suspensions, dispersions or emulsions. This is followed by a rotary tube or equivalent apparatus for calcining. With such prior known methods the losses of powder by cleaning and handling, and also during operation of the plant are or can be considerable; also the labor costs can be high.
Drying and calcining in batches (for example in vessels in a muffle furnace) can be used as an alternative. However, there is the risk with such apparatus of a very wide range of product quality due to diffusion processes and temperature gradients in the powder.
It is therefore an object of the present invention to prepare pulverulent heterogeneous substances and to overcome the disadvantages of prior known methods.